Basic Troubleshooting Tips - HP ProCurve 10 Installation Manual

Troubleshooting

Basic Troubleshooting Tips

Basic Troubleshooting Tips
Most problems are caused by the following situations:
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Incorrect hub-to-switch or hub-to-hub connections. Check your
cable type:
• The HP 10/100 hub ports as standard Ethernet ports, are wired as
MDI-X ports. When connecting to another MDI-X device such as
another hub or switch, use a crossover cable. You can also use a
straight-through cable connected to Port 1 with the MDI/MDI-X
button in the MDI position.
• When connecting to an MDI device such as network interface cards
in computers and other end nodes, and some hub and switch ports,
use a straight-through cable.
See Appendix B, "Cables and Connectors" for pinouts and correct cable
wiring for crossover and straight-through twisted-pair cables.
Non-standard cables. Non-standard and miswired cables may cause
network collisions and noise, and can seriously impair network perfor-
mance. 100Base-T networks are more sensitive to miswired cables than
10Base-T networks, and they must be cabled with Category 5 UTP cable
only. Use a new correctly-wired cable or compare your cable to the cable
in Appendix B, "Cables and Connectors" for pinouts and correct cable
wiring. A category 5 cable tester is a recommended tool for every
100Base-T network installation.
Improper Network Topologies. It is important to make sure you have
a valid network topology. Common topology faults include excessive
cable length and excessive numbers of repeaters between nodes. For
10Base-T networking, the standard allows at most five repeaters (hubs)
between any two end nodes. For 100Base-T, see the topology rules below.
If you have network problems after recent changes to the network, change
back to the previous topology. If you no longer experience the problems,
the new topology is probably at fault. Refer to the guide entitled
Designing HP ProCurve Workgroup Networks for topology configuration
guidelines. This guide can be found online at the HP World Wide Web site,
http://www.hp.com/go/procurve.
In addition, you should make sure that your network topology contains
no data path loops. Between any two end nodes, there should be only one
active cabling path at any time. Data path loops will cause broadcast
storms that will severely impact your network performance.